Many different types of services are available on the web. Examples of services include mapping service, weather services, bookmark services, search engines, and other types of services. In some cases, these services are accessed directly by a user, as in the case where a user explicitly navigates to the site of a mapping service to get a map or directions. In other cases, the services are used by other web sites, as in the case where a restaurant's web site contains a link to a mapping service in order to show the restaurant's location.
Many services have similar functions, and users sometimes favor one service over another. For example, one user might like to view maps on the BING service, while another user might choose to view maps on a different map service. Similarly, users might have opinions about particular weather services, bookmark services, search engines, etc.
When a web site links to a service, the service provider is chosen by whomever creates content for the referring web site. For example, when a restaurant's web site contains a link to a mapping service in order to show the restaurant's location, the link normally points to a particular mapping service. The choice of mapping service is generally an editorial decision of the content-creator of the referring web site. This choice is normally made without regard to which service a particular user would like to use.